Applications requiring a high level of integration of power conversion modules, for example using Switched Mode Power Supplies (SMPS), can resort to power converters such as Switched Capacitor Converters (SCC), which can provide highly efficient DC-to-DC voltage conversion with only the use of capacitors and switches, possibly combined with miniaturized inductive output filters.
Notably, the Solid State Lighting (SSL) Industry's demand for small and compact power management units for LEDs is increasing. LEDs require that power be delivered in the form of a constant current, as efficiently as possible. Ideally, LED drivers comparable in size to the LEDs themselves would represent a significant breakthrough enabling new lighting concepts. Such a solution will require a system with a high level of reliability and efficiency, in order to fit the requirements of life-time, size and heat dissipation.
LED drivers can be based on Switched Mode Power Supplies (SMPS). Notably, some LED drivers can comprise hybrid power converters combining SCCs with inductive SMPS. Recently, LED lamps commonly designated as “smart lamps”, have been developed. Smart lamps typically require drivers having dimmable outputs that provide current control dimmability for supplying the LEDs, as well as providing an auxiliary voltage to supply electronic modules. The electronic modules provide basic lamp control, but can also provide other advanced functionalities such as wireless communication, color dimming, or black bodyline dimming for instance.
According to known solutions, an auxiliary output can be derived from a secondary winding of a transformer, for example by tapping or by using an additional winding. According to other known solutions, a controller, for example implemented in an integrated circuit, are designed to output an auxiliary low voltage by means of dedicated sub-circuits.
However the existing state-of-the art still lacks LED drivers that would integrate in a compact, efficient and optimized manner all the complex requirements in terms of multi-output power management.
The exemplary embodiments described in the current patent application relate to main loads formed by lighting units such as LEDs, but it shall be understood that the current invention can equally apply to other types of linear or non-linear loads, such as CPUs, for instance in mobile device applications, or any type of load requiring output current control and/or a large dynamic range with auxiliary output voltage needs.